Help to ck AC for leaks - Atlanta?? - PeachParts Mercedes-Benz Forum

tyl604 · #1 09-01-2016, 11:30 AM

Anyone in Atlanta who can pressurize my AC to see if I have leaks? My indy does not even fool with R12 anymore. I am considering shooting in some of my three cans of freon. Probably should not do it if I have a leak. 1981 300SD

Thx.

ah-kay · #2 09-01-2016, 12:27 PM

99 300SD? typo? 99 era cars should have R134.

Can you tell from oily deposit? Or use soapy water.

BWhitmore · #3 09-01-2016, 01:11 PM

Most AC shops add dye to the freon (R134) which will then show up most leaks using a UV light.

tyl604 · #4 09-01-2016, 04:38 PM

Corrected year to 1981. Senior moment. Yep, it is R12.

#5 09-01-2016, 09:23 PM

R12 system will have an inspection window in one of the hard lines, a small circular window, usually along radiator core support area on Mercedes.

If you have R12, or a replacement for it... IE Freeze 12 cans, you can fill the system without gauges. Add 1 can to get system going, inspection window will be cloudy white. Keep adding Freon until window turns crystal clear... presto, thats it. DONT add any more. Buy a can of UV dye, usually pressurized in 4 ounce can at parts store. Add to system. Buy a cheap black light. Find the leak yourself easy....

leathermang · #6 09-02-2016, 12:52 PM

Quote:

Originally Posted by 83240D

R12 system will have an inspection window in one of the hard lines, a small circular window, usually along radiator core support area on Mercedes.

If you have R12, or a replacement for it... IE Freeze 12 cans, you can fill the system without gauges. Add 1 can to get system going, inspection window will be cloudy white. Keep adding Freon until window turns crystal clear... presto, thats it. DONT add any more. Buy a can of UV dye, usually pressurized in 4 ounce can at parts store. Add to system. Buy a cheap black light. Find the leak yourself easy....

A post full of BAD information.
As just one point... the MB AC FSM specifically warns against using the sight glass for determining the refrigerant fill level because it can show bubbles even with the CORRECT fill ... meaning if you follow this guys advice you can way over fill your AC system... there are other false statements easily researched ... but that should warn you as to the danger of believing this poster...

tyl604 · #7 09-02-2016, 01:05 PM

Leathermang - yes, I am well aware. The purpose of this thread is to see if anyone in Atlanta can pressurize the system so I can check for leaks. Before I put three cans (FSM says 48 oz) of Freon in at a cost to me of $100.

All has leaked out over the course of about four years.

leathermang · #8 09-02-2016, 01:10 PM

Quote:

Originally Posted by tyl604

Leathermang - yes, I am well aware. The purpose of this thread is to see if anyone in Atlanta can pressurize the system so I can check for leaks. Before I put three cans (FSM says 48 oz) of Freon in at a cost to me of $100.

All has leaked out over the course of about four years.

I know YOU are...
but he did not send that information to you in a PM..
others, not as familiar with the physics of the situation, will read it and might consider it legit advice...
Remember, threads are not just for the OP... but for everyone to learn from.

tyl604 · #9 09-02-2016, 01:14 PM

Right. Good thinking.

A friend has a set of R12 gauges. So you think I can just by some nitrogen cans on the internet and install it just like freon? What about dye?

leathermang · #10 09-02-2016, 01:29 PM

Quote:

Originally Posted by tyl604

Right. Good thinking.

A friend has a set of R12 gauges. So you think I can just by some nitrogen cans on the internet and install it just like freon? What about dye?

Ok. so you are considering DIY in case a person is not available as per your original question ?

I do not know what size nitrogen cans are available for sale... or can be shipped or whatever...

but I suspect that ANY local welding supply ( where I bought mine ) will have them available both to buy or to rent... and I think lately someone dealing with small cans of stuff found that they did not contain enough to do their project correctly.. perhaps when it will be needed at least twice by my calculation.. to find the leak and to check to see if your fix worked.
what you can buy I think.. is the legal R22 can in approx 16 oz .. which would provide three or four test batches when installed with the Nitrogen..
So, yes , a pain, and seems like a large expense... relatively... and I hope you simply find someone who can do what your original question asked..
but in the alternative... this seems much better and provides a way for a sniffer to find the leak... I have scant confidence in liquid leak detectors due to how hard it is to see dirty lines in the engine compartment and any of the evaporator...
My first MB wagon had an evaporator leak... using a sniffer at the middle vent... clean, fast , accurate.... and does not put any ' foreign ' stuff like dye into the system..

tyl604 · #11 09-02-2016, 02:57 PM

leathermang - found this: https://www.amazon.com/Disposable-Tank-of-Nitrogen-Filled/dp/B013KC9FUK/ref=sr_1_1?s=automotive&ie=UTF8&qid=1472841744&sr=1-1&keywords=nitrogen+gas#Ask Total $28 incl shipping but reading the comments some say the bottle arrived empty. The sellers will not tell you how much N2 is in the bottle either.

Welding supply co. Interesting. Are you saying pressurize it with R22 (no idea what this unless it is a refrigerant between R12 and R134a) plus N2 or not to use N2?

Yes, may have to try to do it myself. Not getting many comments from the forum. Odd.

tyl604 · #12 09-02-2016, 03:06 PM

Leather - Is R22 ok to use; will it contaminate the system which is R12? I see that R22 is house refrigerant.

leathermang · #13 09-02-2016, 03:29 PM

The last I knew... the EPA authorized the use of four oz of R22 added to nitrogen to check for leaks AND allows it to be vented into the atmosphere..
The theory is that it is better to allow some ( sniff reactive ) refrigerant into the atmosphere to keep people from just ignoring leaks and losing more , much more, over the long run..

R22 as a trace with Nitrogen in R410 system.

Demothen · #14 09-02-2016, 03:32 PM

That disposable can of nitrogen should get your system up to at least 90psi, probably more. I had lost a bit of mine when i last charged it and got to 90 before equalizing. You need the regulator that the amazon seller sells on their site though as it uses a schraeder valve

leathermang · #15 09-02-2016, 03:37 PM

Quote:

Originally Posted by Demothen

That disposable can of nitrogen should get your system up to at least 90psi, probably more. I had lost a bit of mine when i last charged it and got to 90 before equalizing. You need the regulator that the amazon seller sells on their site though as it uses a schraeder valve

What size disposable can did you have ?
How much did it cost and from where ?
Would it do three tests ?